DERIVATIVE FINANCIAL INSTRUMENTS - DERIVATIVE NOTIONALS (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Notional amount of derivative	$ 306	$ 306
Foreign Exchange [Member]
Derivative [Line Items]
Notional amount of derivative	1,084	1,158
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional amount of derivative	1,430	594
San Diego Gas and Electric Company [Member] | Interest Rate Swap maturing on October 31 2019 [Member]
Derivative [Line Items]
Notional amount of derivative	159
San Diego Gas and Electric Company [Member] | Swaption [Member]
Derivative [Line Items]
Notional amount of derivative	142
San Diego Gas and Electric Company [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Notional amount of derivative	$ 142	$ 142
Maximum [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Derivative, Maturity Date	Dec. 31, 2023	Dec. 31, 2023
Maximum [Member] | Foreign Exchange [Member]
Derivative [Line Items]
Derivative, Maturity Date	Dec. 31, 2020	Dec. 31, 2020
Maximum [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Maturity Date	Dec. 31, 2032	Dec. 31, 2032
Maximum [Member] | San Diego Gas and Electric Company [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Maturity Date	Dec. 31, 2019	Dec. 31, 2019
Minimum [Member] | Interest rate and foreign exchange instruments [Member]
Derivative [Line Items]
Derivative, Maturity Date	Dec. 31, 2019	Dec. 31, 2019
Minimum [Member] | Foreign Exchange [Member]
Derivative [Line Items]
Derivative, Maturity Date	Dec. 31, 2019	Dec. 31, 2019
Minimum [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Maturity Date	Dec. 31, 2019	Dec. 31, 2019
Minimum [Member] | San Diego Gas and Electric Company [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Maturity Date	Dec. 31, 2019	Dec. 31, 2019